Why does my 2018–2020 Ford Expedition rattle for a few seconds when I start it cold?

Short answer: A harsh rattle or buzz that lasts 2–5 seconds right after starting a 2018–2020 Expedition that has sat for hours is the classic sign of worn cam phasers (also called VCT units: the parts on the ends of the camshafts that adjust valve timing). Ford's bulletin 20-2315 has dealers replace all four and update the engine software. Ford's extended coverage for this ended January 1, 2023, so it's usually a paid repair now. A softer ticking that lasts a minute or two is more often the turbo wastegates, a separate issue.

Symptom: A loud rattle, buzz or grinding sound from the front of the engine for a few seconds after a cold start (after sitting 6 hours or more), then it runs normally.

What to check first

1. Record the sound on a cold start in the morning. The dealer needs to hear it, and it's gone in seconds.
2. Time it. Owners say a 2–3 second harsh buzz is the cam phasers; a lighter ticking that lasts 90–120 seconds is more often the turbo wastegates.
3. Ask the dealer whether program 21B10 (software) and 21N03 were done on your VIN, and whether any cam phaser work is on record.
4. Check engine light? Have the codes read. Timing-related codes help confirm it.

Likely causes

1. Worn cam phasers (VCT units). Ford's TSB 20-2315 says a worn variable camshaft timing unit can make a 2–5 second ticking or rattle after a cold soak of 6 hours or more.
2. Turbo wastegate rattle. An Expedition Forum owner explained the wastegate rattle is softer, lasts about 90–120 seconds, and isn't fixed by the software update.

What it usually costs

Ford's program 21N03 covered cam phaser replacement on a sliding scale by mileage, but only until January 1, 2023 and only if the 21B10 software update was done first. Owners in these threads had the work done under warranty and didn't post out-of-pocket prices. Get a written quote for replacing all four phasers.

Is it safe to keep driving?

Ford says the noise itself doesn't affect safety, performance or emissions, and its bulletin says owners can keep driving while parts are on order. If the rattle gets longer, a check engine light comes on, or it runs rough, get it checked soon. Verify with a mechanic.

DIY or shop?

Shop. Replacing cam phasers means taking off the front engine cover and timing the engine.

Recalls, bulletins and complaints in plain words

• TSB 20-2315 (technical service bulletin, a repair guide Ford sends dealers): 2017–2020 F-150 and 2018–2020 Expedition and Navigator with the 3.5L EcoBoost built on or before October 31, 2019 can tick or rattle for 2–5 seconds after a cold soak because of worn VCT units. Dealers replace the VCT units and update the engine software.
• Customer Satisfaction Program 21N03: extended cam phaser coverage until January 1, 2023 for trucks that got the 21B10 software update on time, paying 100% up to 69,999 miles on Fords and less above that. That coverage has ended.
• Recall 18V392 (2018 Expedition, separate issue): high pressure fuel pump welds can fracture and leak oil or fuel. Recall 25V628 (some 2020 Expedition, separate issue): a short in the battery junction box can cause an engine fire; owners are told to park outside until it's fixed. If your truck is part of a recall, the dealer fixes it for free.
• NHTSA complaints: 245 keyword-matched complaints for Ford Expedition 2018–2020 (of 1,320 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-18; keywords: rattle, phaser, cam, camshaft, timing, vct, tick, startup, start up, cold start) (NHTSA returned no complaint data for 3 model-year queries).

What owners report

• In Phaser recall on Expedition Forum, an owner whose truck still rattled after the software update was told to give it 1,000 miles. A member explained the update is meant to prevent phaser damage, not fix it, and described the difference between the short phaser buzz and the longer wastegate rattle. Another owner had the phasers replaced under warranty.
• On r/fordexpedition, owners asked whether the cold start rattle ever goes away on its own.

My take

My advice as a former car salesman: when I'm looking at a used 2018–2020 Expedition, I ask to start it cold. If it buzzes for a few seconds, I ask for proof the phasers were replaced, and if not, the repair comes off the price.

Vehicle focus: 2018–2020 Ford Expedition and Expedition Max with the 3.5L EcoBoost (also 2018–2020 Navigator and 2017–2020 F-150).

Safety / mechanic note

Engine timing problems can get worse if ignored. Verify with a mechanic.